Evolution: Hunting Began 1.5 Million Years Ago, Says Scientist

"Scavenging is very opportunistic," Musiba said. It depends on another animal making the kill, and then abandoning its own dinner. That would suggest that if our ancestors were used to meat, but dependent on others for the kill, they would probably have faced frequent and severe shortages. So many of the bones discovered in Olduvai Gorge should show vitamin deficiencies.

"We looked for that" in many other bones from that region, Musiba said, "but we didn't see it."

Musiba and his team, which includes anthropologists from Spain, South Africa, France and the United States, are currently studying the bones of animals recovered from the same site. They show the marks of tools, so they were obviously skinned and eaten by our ancestors, but were they also hunted?

Musiba thinks they were, partly because some marks show repeated blows, suggesting the animal was attacked while it was still alive. That research has not yet been published for other scientists to scrutinize.

"There is information which strongly suggests active hunting was prevalent by 1.5 million years ago," Musiba said.

It would not have been as difficult as might seem, even though the weapons – if they were weapons – were pretty limited. They didn't have spears, or projectiles of any kind, so they would probably beat a large animal over the head with a chunk of rock.

"Ambush is the best method," Musiba said. "You would know your landscape very well, and you would know where the animals would be congregating. It wouldn't be that difficult."

Still, the message in that tiny piece of bone is clear. For our ancestors, nothing came easy.

"The child had to have had a stressed diet for a long period of time, from three to six months, or even a year," he said. "Imagine dying at two years old of malnutrition."